1. Field of the Invention
The present invention relates to an inkjet printing machine that discharges ink from an inkjet head to perform printing.
2. Description of the Related Art
An inkjet printing machine that discharges an ink drop on a printing medium from a nozzle while moving an inkjet head including a plurality of nozzles, has been known in the art (See, for example, Japanese Patent Application Laid-Open No. 2005-262581). Such an inkjet printing machine is sometimes used to perform printing on a building material or on a surface of a decorative panel, which is so-called decoration.
Since such a building material or the like often has a heavy weight, the decoration employs a method in which the building material or the like, which is a target of the decoration, is arranged and fixed on a table and then printing is performed while an inkjet head unit is moved in a main-scanning direction. In this method, while an inkjet head is moved in the main-scanning direction, printing for pixels in a prescribed pitch width is performed. The inkjet head is then moved in a sub-scanning direction by the pitch width and printing for a next pitch width is performed.
However, in the inkjet printing machine that employs the above-described method of repeating a movement of the inkjet head unit in the main-scanning direction and a movement of the inkjet head unit in the sub-scanning direction, immediately after moved in the sub-scanning direction, the inkjet head unit vibrates in the moved direction. Residual vibration due to the movement may cause landing misalignment of ink drops, which brings degradation in printing quality. This conventionally requires stops of printing until the vibration immediately after the inkjet head unit is moved in the sub-scanning direction converges. As a result, there is a problem that the amount of printing per unit time is limited. To improve the productivity, recent inkjet printing machines tend to have the increased number of mounted inkjet heads along the increased number of nozzles of inkjet heads, and thus have the significantly increased weight of the inkjet head unit. With the increase in the weight of the inkjet head unit, convergence time of the vibration due to the movement of the inkjet head unit is delayed. If the printing is performed after the vibration converges, there is a problem that the productivity drops.